#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
int missingNumber(int* nums, int numsSize)
{
    int n = numsSize;
    int sum = (n * n + n) / 2;

    for (int i = 0; i < numsSize; i++)
    {
        sum -= nums[i];
    }
    return sum;

}
int main()
{


	return 0;
}